This is true, although I find it interesting that so many people then gravitate to Costco, where consumer choice in a given category is deliberately restricted to one or two product variations selected by the head office.
Also, you don't have to shop at Costco exclusively, you still have all the other options available. Costco is just a good default if you're not looking for something specific.
Meanwhile in Europe I spend many evening on internet forums and Facebook groups doing research trying to find a part that will work with my car, then finding someone willing to sell it and finally using Google Translate getting someone to ship it to my foreign (to them) country. I even had to resort to proxies just to get car parts from Eastern to Western Europe.
They're not mutually exclusive, two things can be had at the same time.
Wish to live in your reality tho, where I can buy a dozen different brands of hot dogs while visiting the doctor for elevated blood pressure without needing to take out a payment plan on klarna.